Finding Conjugate Acids and Bases

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Lauren Ton 4B
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Joined: Fri Sep 26, 2014 2:02 pm

Finding Conjugate Acids and Bases

Postby Lauren Ton 4B » Mon Dec 08, 2014 12:16 am

When you're trying to find a conjugate acid or a conjugate base of a molecule that has multiple H's, how do you know which one to take away/add to?

For example, finding the conjugate base of CH3COOH?

Jose A Guerrero 1F
Posts: 6
Joined: Wed Oct 01, 2014 3:00 am

Re: Finding Conjugate Acids and Bases

Postby Jose A Guerrero 1F » Mon Dec 08, 2014 1:18 am

An easy way to remember when to add or subtract is to remember the following:

A basic person accepts things as they are. Similarly, a base in chemistry accepts 'H's.

Treat CH3COOH as the result of the base accepting an 'H'. To find the conjugate base, simply remove the 'H'.
Conjugate base: CH3COO-

504420311
Posts: 9
Joined: Fri Sep 26, 2014 2:02 pm

Re: Finding Conjugate Acids and Bases

Postby 504420311 » Thu Dec 11, 2014 2:22 pm

With a molecule with multiple H's, it is helpful to draw a Lewis structure to see which bond to break, for example if you took away an H from the H in CH3, the carbon would be missing a bond, however, by taking a H off the O, it is easier to just replace the missing electron with a missing charge. In a lot of molecules, it seems as if the O is the bonding atom to the H because of its electronegativity, so its easier for it to pick up H protons in water.

Shaye Busse 3B
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

Re: Finding Conjugate Acids and Bases

Postby Shaye Busse 3B » Sat Nov 14, 2015 10:34 pm

Lauren Ton 4B wrote:When you're trying to find a conjugate acid or a conjugate base of a molecule that has multiple H's, how do you know which one to take away/add to?

For example, finding the conjugate base of CH3COOH?


Excellent question. The answer to this is actually far simpler than it may first appear. In order to find the conjugate base of an acid, you must first think about what kind of base would give you that acid after it accepts a proton. In the case of CH3COOH specifically, the base that accepts the acid to give acetic acid would be CH3COO-. This same process can be done to find any conjugate acid or base.


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